81959744 has 28 divisors (see below), whose sum is σ = 164477700. Its totient is φ = 40516608.

The previous prime is 81959743. The next prime is 81959777. The reversal of 81959744 is 44795918.

It can be written as a sum of positive squares in 2 ways, for example, as 19360000 + 62599744 = 4400^2 + 7912^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81959743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1499 + ... + 12890.

Almost surely, 2^81959744 is an apocalyptic number.

It is an amenable number.

81959744 is an abundant number, since it is smaller than the sum of its proper divisors (82517956).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81959744 is a wasteful number, since it uses less digits than its factorization.

81959744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14490 (or 14480 counting only the distinct ones).

The product of its digits is 362880, while the sum is 47.

The square root of 81959744 is about 9053.1620995098. The cubic root of 81959744 is about 434.3770428557.

The spelling of 81959744 in words is "eighty-one million, nine hundred fifty-nine thousand, seven hundred forty-four".